CCNA Switching and Network Access Practice Question
A campus switch has VLANs 10, 20, and 30 configured. Port GigabitEthernet0/5 connects to a server that must send and receive traffic for all three VLANs, and the server's NIC supports 802.1Q tagging. The administrator wants the server to handle VLAN tagging itself. Which configuration on GigabitEthernet0/5 is appropriate?
⚠ Common exam trap
The trap here is assuming an access port can carry multiple VLANs if the NIC tags frames, but access ports do not forward tagged traffic for other VLANs.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
switchport mode trunk and switchport trunk allowed vlan 10,20,30
When a server NIC performs 802.1Q tagging itself, the switch port must be a trunk so tagged frames for multiple VLANs can pass. Restricting the allowed VLAN list to 10, 20, and 30 limits unnecessary traffic and matches the requirement. A static trunk avoids DTP negotiation issues with a server that does not run DTP.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
switchport mode access and switchport access vlan 10
Why it's wrong here
An access port places all untagged traffic into a single VLAN, here VLAN 10, so the server could not reach VLANs 20 and 30. Even though the NIC supports tagging, an access port strips or ignores VLAN tags from the server, so the multi-VLAN requirement would fail and the server would only communicate within VLAN 10.
- ✗
switchport mode trunk, switchport trunk native vlan 10, and switchport access vlan 20
Why it's wrong here
Combining trunk mode with an access VLAN command is a configuration conflict because access VLAN assignment applies to access ports, not trunk ports. The native VLAN setting would place untagged traffic in VLAN 10, but the allowed VLAN list is missing, so VLANs 20 and 30 would not be carried and the server could not use all three VLANs.
- ✓
switchport mode trunk and switchport trunk allowed vlan 10,20,30
Why this is correct
A trunk port with the allowed VLAN list permits the server to send and receive tagged frames for VLANs 10, 20, and 30. Because the server NIC supports 802.1Q, it can create and interpret the tags itself, so the switch does not need to assign an access VLAN. This matches the requirement for a single interface carrying multiple VLANs.
- ✗
switchport mode dynamic desirable and switchport trunk allowed vlan 10,20,30
Why it's wrong here
Dynamic desirable actively attempts to negotiate a trunk using DTP, which is unnecessary and potentially insecure when the attached device is a server. A server NIC does not participate in DTP, so the port would not reliably become a trunk. Statically configuring trunk mode is the appropriate and deterministic choice for a server carrying multiple VLANs.
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Related to this question
Learn chapter
TCP Three-Way Handshake
Key term
VLAN
A VLAN (Virtual Local Area Network) is a logical grouping of network devices that behave as if they are on the same physical network segment, regardless of their actual physical location.
Key term
NIC
A NIC is a hardware component that connects a computer to a network, enabling communication over wired or wireless media.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.